Unpublished observations from this laboratory strongly suggest that neuronal activity in the hypothalamic area of the rat is markedly depressed during acute exposure to methyl methacrylate monomer (MMA) vapor. The object of this study is to further evaluate the effects of MMA on the central nervous system of the Sprague Dawley rat. It is proposed to study the effects of acute exposure to the vapor by monitoring the cortical EEG and multiple unit activity from those brain regions involved in the regulation of gastrointestinal function. We also intend to determine if chronic exposure to the vapor alters those neuronal structures found to be acutely affected over a longer period of time and to determine the dose level at which this effect is observed.